Valve for instant hot water system

ABSTRACT

An instant hot water system has a return line from the far end of the hot water supply line back to the cold water inlet of the water heater. At the junction between the return line and the cold water supply line, there is a piston valve which closes the return line when cold water flows into the heater to replace hot water drawn off. The piston valve member, spring pressed to a position normally closing the cold water inlet and opening the connection to the return line, is of molded plastic material.

er system has a return line supply line back to the cold At the junction between the pply line, there is a piston cold water flows into off. The piston valve mally closing the cold [56] References Cited UNITED STATES PATEN TS 2,106,822 2/1938 White..................... 2,915,080 12/1959 Holmes 3,097,661 7/1963 Primary Examiner-Robert G. Nilson Artorneys-Charles Shepard and Stonebraker & Shepard ABSTRACT: An instant hot wat from the far end of the hot water water inlet of the water heater. return line and the cold water su valve which closes the return line when the heater to replace hot water drawn member, spring pressed to a position nor water inlet and opening the connection to the return line, is of molded plastic material.

Robert A. Walton Rochester, N.Y. Appl. No. 754,171 [22] Filed Aug. 21, 1968 [45] Patented Jan. 19, 1971 [73] Assignee W. F. Products Corp.

Fishers, N.Y. a corporation of New York 7 Claims, 3 Drawing Figs. [52] 11.8. 137/112, 137/337, 137/564 F24h 9/12 137/112, 337,564

United States Patent [72] Inventor [54] VALVE FOR INSTANT HOT WATER SYSTEM [50] Field ofSearch.....

j a a w Ill i ant/mm V PATENT EM 9min I Egg a N .0. WM w 7 3 3 VALVE FOR INSTANT HOT WATER SYSTEM BACKGROUND OF THE INVENTION In most hot water systems as used in homes, apartments, and commercial buildings of moderate cost, there is a single hot water supply line going from a hot water heater (usually in the basement) to the various hot water faucets such as those at the kitchen sink and at wash basins and bathtubs on the second floor. Usually no provision is' made for circulation of water in the hot water supply line, so that during the intervals between the times when hot water is drawn off, the hot water remains stationary in the supply line and gradually cools. Therefore, if a faucet is opened at some distance from the hot water heater, at a substantial time interval (15 minutes or more) since the last time thatwater was d awn from this faucet, the flow of waterwill be quite cool, and then after the cooled water between the heater and the faucet has been drawn off, the water will run hot. The wait for the water to run hot is often quite annoying, and also the sudden advent of hot water after a substantial flow of relatively cool water can be quite discomforting.

This can be avoided if a return line is provided from the remote end of the hot water supply line back to the cool connection of the hot water heater. This enables the water to circulate slowly in the hot water supply line, similar to circulation in a hot water heating system, so that as soon as a hot water faucet is opened, even at a point quite remote from the hot water heater, the water will flow out hot rather than cold.

Such a system, including a return line, is already known, and is frequently called an instant hot water system. Such a system has not gone into widespread use, however, because such a system, as used heretofore, is subject to having a considerable amount of cold water back up in the return line, and this interferes with quick resumption of the intended circulating flow after the faucet is turned off. Accordingly, the so-called instant hot water systems of the prior art have not worked very well. Attempts have been made to use valves to prevent the undesirable backing up of cold water in the return line, but such valves have either been expensive to make or unsatisfactory in operation, or both.

An object of the present invention is the provision of a generally improved and more satisfactory valve at the junction between the cold water inlet of the water heater, and the circulation return line.

Another object is the provision of such a valve so designed that it is economical to manufacture, easy to install, andhighly efficient and satisfactory in use.

BRIEF DESCRIPTION OF THE DEAWING In the accompanying drawing, incorporated herein by reference and constituting a material part of the disclosure and relating to an exemplary embodiment of the invention:

FIG. 1 is a schematic view of an instant hot water system, including the valve of the present invention;

FIG. 2 is a vertical section taken diametrically through the valve in its preferred form, the section being approximately on the line 2-2 of FIG. 3; and

FIG. 3 is a horizontal section taken approximately on the line 33 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, there is shown rather schematically a hot water system comprising a conventional water heater 11, and a hot water supply pipe 13 leading from the top of the hot water tank of the heater to any point where hot water is desired, such as the point where the faucet 15 is located. As hot water is drawn off, it is replaced, in the conventional way, by cold water coming in throughthe cold water supply pipe 17. In some. forms of heater, the supply pipe enters the top of the tank and leads down within the tank, at 19, to a point near the bottom thereof, so that incoming cold water does not too greatly cool the hot water near the top of the tank 11. In other forms of heater, the cold water supply may enter the tank on the side or at the bottom. Such details are immaterial so far as the present invention is concerned.

For circulation of hot water in the supply pipe 13, to keep this water hot during the intervals when no water is being drawn off through the faucet 15, there is a return line 21 from the most remote point of the hot water supply line 13 back to the water heater. There may be several faucets on the line 13,

and it is sufficient to have a single return line 21 from a point.

near the most remote faucet. However, in some houses or apartments, various bathrooms are separated so widely from each other that it is necessary to have more than one hot water supply line going from the heater to various locations, and in such a situation, there would be a return line 21 from the most.

remote point of each separate supply line 13.

In most cases, the circulation return line 21 can be quite small compared to the size of the hot water supply line 13. Adequate circulation is usually achieved, in a small installation, by using a return line 21 having a nominal diameter of one-fourth inch, if the supply line 13 has a nominal diameter of one-half inch or three-fourths of an inch. ln larger installations, a return line of larger size may be desirable. The return line 21 preferably has a constant slope from the remote end back to the hot water heater, but this is not essential so long as each approximately horizontal run of the return line is below the corresponding horizontal run ofthe supply line.

Attempts have been made to connect a return line such as shown at 21, to the cold water inlet line 17, merelyby an ordinary T-fitting. However, this does not work satisfactorily. When the faucet 15 is opened to discharge water, even though most of the water flows to the faucet through the hot water supply line 13, there would bea tendency for some water to flow toward the faucet through the return line 21. Since the lower end of the return line 21 is connected to the cold water inlet line 17, cold water would be drawn up the return line 21'. Even if such cold water does not reach the faucet 15, it nevertheless chills the line 21 to a sufficient extent to interfere with the desired circulating flow in the system, which circulating flow should start immediately after the valve 15 is shut off.

If the water in the return line 21 is chilled, it may take quite a.

time, half an hour or an hour or more, for the circulation to start.

To overcome this difficulty, attempts have been made to use an ordinary check valve at the point where the returnline 21 connects with the cold water inlet line 17. While the use of a check valve may preventcold water from backing up in the line 21, yet it is not satisfactory because it tends to obstruct the flow coming down the circulation return pipe 21.'lt must.

be realized that, when the system is working at maximum effectiveness, there is only a slight difference in temperature between the hot water flowing up the main supply line 13 and the slightly cooler water circulating down the return line 21,,

so that there is not very much pressure available for opening a check valve. A conventional check valve, opened by flow and closed by gravity, simply produces too much resistance.

The valve of the present invention overcomes this difficulty, leaves the connection from the return line 21 completely open when it should be open, and closes it effectively when cold water flows into the hot water tank to replace hot water which is being drawn off. The valve, shown especially in FIGS. 2 and 3, has a main body section 31 which may be of metal but preferably is of plastic material. It is formed with suitable means for connection to the desired pipes; for example, with pipe threads 33 at the top for connection to the incoming cold water pipe 17, and pipe threads 35 at the bottom for connection to the pipe 19 which goes down into the tank to a point near the bottom thereof. It is immaterial for purposes of the.

present invention whether the connections are threaded connections as here illustrated, or whether they are connections of any other known type, such asflared connections or compression fittings. The same choice as to style of connections applies also to a side connection 37 formed with threads or other connecting means for connection to the return circulation pipe 21. .Aport 39 is provided, extending fromrzthis con- .nection 37 into the main central chamber 41 of the valve body.

This chamber 41 is cylindrical, and has an integral annular flange 43 at its top, just below the threads 33. Movable in the chamber is a piston valve, preferably of molded plastic materia1, comprising a central stem 51, a head 53, and a piston member 55 at an intermediate point of the stem 51.

The head 53 has a sufficient diameter to close the central opening in the partition 43 when the valve is in its uppermost position, but the diameter of the head 53 is of sufficiently smaller size than the internal diameter of the chamber 41 so that there is plenty of room around the head for water to pass downwardly around the edges.

The piston portion 55 is relatively thick in an axial direction, and is perforated with a number of large axial holes 57 as seen in FIG. 3. The periphery of the piston portion 55 fits snugly but easily slidably against the sidewalls of the chamber 41. On the lower portion of the stem 51 below the piston 55 is a coiled spring 61, pressing upwardly on the piston portion 55 and reacting downwardly on a diametrical plate 63 which has a central opening slidably receiving the stem 51. The ends of the diametrical plate are held in place against shoulders 65 on the valve body by any suitable retaining means such as the split ring 67 seated in an annular groove formed internally in the body.

When no water is flowing into the upper end of the valve from the cold water inlet 17, the spring 61 keeps the valve in its uppermost position illustrated in FIG. 2. In this position, the piston portion 55 lies just above the port 39 which establishes connection between the interior of the valve body and lower end of the circulation return line 21. Thus circulation of the hot water may occur rather freely, with the hottest water rising from the top of the tank through the main hot water line 13, and the still not but slightly cooler water coming down through the return line 21, through the port 39 into the portion ofthe valve body which is below the piston 55, and then down past the retainer 63 and into the pipe 19 to the bottom of the tank. The circulation is not impeded by having to push against any valve to open it, as is the case when using a conventional check valve. 7

However, when the faucet (or any faucet, of course, connected to the system) is opened, cold water under pressure comes in through the cold water inlet 17 to replace the hot water drawn off. Immediately when the cold water inflow starts, the pressure of the incoming cold water acting on the valve head 53 pushes thisvalve member downwardly against the slight force of the spring 61, down to a point where the piston portion 55 covers the port 39 and prevents any of the incoming cold water from entering the port 39 and backing up the circulation return line 21. Thus no water flows in the line 21 so long as the faucet 15 is open.

As soon as the faucet is closed, there is no further inflow through the cold water supply 17, consequently no more pressure against the top of the valve member 53 and therefore the spring 61 moves the valve member upwardly to its normal rest position, immediately uncovering or opening the port 39 so that the circulation can immediately resume.

A noteworthy point is that because the valve member 51, 53, 55 is of plastic material, it does not corrode, and scale does not readily form thereon even if used in a region having hard water. The valve piston portion 55 slides easily up and down in the chamber 41. As above stated, the valve body 31 may be of metal, but when it is made of plastic material, like the valve member itself, a very smooth and low-friction action results.

Since the valve member 51, 53, 55 is completely symmetrical about its central axis, it does not need to be inserted in the valve body in any particular position of orientation. If it turns a little while in use, this does not matter.

It is to be understood that the disclosure is given by way of illustrative example only, rather than by way of limitation, and

that without departing from the invention, the details may be varied within the scope of the appended claims.

I claim: 1. An instant hot water system comprising: a hot water tank,

a hot water supply line heading from said tank to a remote point where hot water is to be drawn off, a cold water supply line for supplying cold water to said tank to replace hot water drawn off therefrom, a water circulation return line operatively connected to said hot water supply line near said remote point and leading thence to said cold water supply line near said tank, said return line opening freely into said cold water supply line without substantial obstruction so long as no incoming cold water is flowing in said cold water supply line, and means operated by flow of incoming cold water for substantially closing the opening of said return line into said cold water supply line, said means for substantially closing the opening of said return line comprising a hollow valve body having a cold water inlet, an outlet, and a port connected to said return line, a movable valve member having a portion adapted to uncover said port when said valve member is in a first position and to cover said port when said valve member is in a second position, a spring tending to move said valve member to said first position, and a portion on said valve member displaced by inflow of water into said inlet to move said valve member from said first position to said second position against the force of said spring, said valve body having a substantially cylindrical chamber with said port formed in a lateral wall thereof and with a transverse wall apertured to form an inlet orifice at an inlet end of said chamber, said valve member comprising a stem portion extending axially in said chamber, a piston portion surrounding said stern portion and engaging the walls of said chamber to cover said port when said valve member is in said second position and to uncover said port when said valve member is in said first position, and a head portion on said stem for cooperating with said transverse wall to close the inlet orifice when said valve member is in said first position.

2. A construction as defined in claim 1, in which said piston portion of said valve member has a plurality of passages extending through the thickness of said piston portion in an axial direction.

3. A construction as defined in claim 1, in which at least the piston portion of said valve member is formed of plastic material.

4. A constructibn as defined in claim 1, further including a valve stem guide member extending transversely across said chamber and engaging and guiding said sterrrportion at a point thereof on the opposite side of said piston portion from said head portion.

5. A construction as defined in claim 4, further including a coil spring surrounding said stem portion between said guide member and said piston portion, said spring reacting against said guide member and pressing axially against and piston portion in a direction tending to move said valve member to said first position and to seat said head portion thereof in closing relation to said inlet orifice.

6. A valve for connecting a cold water supply line to a hot water circulation return line in an instant hot water system: said valve comprising a tubular body having a cylindrical chamber therein with an inlet end adapted to be connected to a cold water supply line, and an outlet end, a lateral port in a sidewall of said chamber, said port being adapted to be connected to said hot water circulation return line; a transverse wall near the inlet end of said chamber, said wall being apertured to form an inlet orifice; a valve member movable axially within said chamber; said valve member having a central stern extending axially, a head at one end of said stem, and a piston portion at an intermediate point on the length of said stem; said head being of a size to close said inlet orifice when said head is seated against said transverse wall and being of smaller diameter than said chamber so that water may flow past the peripheral edge of said head when said head is moved axially away from said transverse wall; said piston portion having openings extending axially therethrough so that water may against said transverse wall to close said inlet orifice, so that water may then flow from said port into said chamber and thence out said outlet end.

7. A construction as defined in claim 6, further comprising a coil spring surrounding said stem and tending to move said valve member axially to maintain said head in closing relation to said inlet orifice. 

1. An instant hot water system comprising: a hot water tank, a hot water supply line heading from said tank to a remote point where hot water is to be drawn off, a cold water supply line for supplying cold water to said tank to replace hot water drawn off therefrom, a water circulation return line operatively connected to said hot water supply line near said remote point and leading thence to said cold water supply line near said tank, said return line opening freely into said cold water supply line without substantial obstruction so long as no incoming cold water is flowing in said cold water supply line, and means operated by flow of incoming cold water for substantially closing the opening of said return line into said cold water supply line, said means for substantially closing the opening of said return line comprising a hollow valve body having a cold water inlet, an outlet, and a port connected to said return line, a movable valve member having a portion adapted to uncover said port when said valve member is in a first position and to cover said port when said valve member is in a second position, a spring tending to move said valve member to said first position, and a portion on said valve member displaced by inflow of water into said inlet to move said valve member from said first position to said second position against the force of said spring, said valve body having a substantially cylindrical chamber with said port formed in a lateral wall thereof and with a transverse wall apertured to form an inlet orifice at an inlet end of said chamber, said valve member comprising a stem portion extending axially in said chamber, a piston portion surrounding said stem portion and engaging the walls of said chamber to cover said port when said valve member is in said second position and to uncover said port when said valve member is in said first position, and a head portion on said stem for cooperating with said transverse wall to close the inlet orifice when said valve member is in said first position.
 2. A construction as defined in claim 1, in which said piston portion of said valve member has a plurality of passages extending through the thickness of said piston portion in an axial direction.
 3. A construction as defined in claim 1, in which at least the piston portion of said valve member is formed of plastic material.
 4. A construction as defined in claim 1, further including a valve stem guide mEmber extending transversely across said chamber and engaging and guiding said stem portion at a point thereof on the opposite side of said piston portion from said head portion.
 5. A construction as defined in claim 4, further including a coil spring surrounding said stem portion between said guide member and said piston portion, said spring reacting against said guide member and pressing axially against and piston portion in a direction tending to move said valve member to said first position and to seat said head portion thereof in closing relation to said inlet orifice.
 6. A valve for connecting a cold water supply line to a hot water circulation return line in an instant hot water system: said valve comprising a tubular body having a cylindrical chamber therein with an inlet end adapted to be connected to a cold water supply line, and an outlet end, a lateral port in a sidewall of said chamber, said port being adapted to be connected to said hot water circulation return line; a transverse wall near the inlet end of said chamber, said wall being apertured to form an inlet orifice; a valve member movable axially within said chamber; said valve member having a central stem extending axially, a head at one end of said stem, and a piston portion at an intermediate point on the length of said stem; said head being of a size to close said inlet orifice when said head is seated against said transverse wall and being of smaller diameter than said chamber so that water may flow past the peripheral edge of said head when said head is moved axially away from said transverse wall; said piston portion having openings extending axially therethrough so that water may flow through said piston portion and having a peripheral edge slidably engaging the sidewalls of said chamber in the vicinity of said lateral port and positioned to cover and block said lateral port when said head is moved axially away from said transverse wall; so that water may then flow in said inlet orifice, past said head, through said piston, and out said outlet end without flowing into said port, said peripheral edge of said piston uncovering said lateral port when said head is seated against said transverse wall to close said inlet orifice, so that water may then flow from said port into said chamber and thence out said outlet end.
 7. A construction as defined in claim 6, further comprising a coil spring surrounding said stem and tending to move said valve member axially to maintain said head in closing relation to said inlet orifice. 